The invention relates to a tooling system for operations like stamping, piercing, cutting, bending or forming work on electronic, electromechanical or mechanical components, particularly for removing the tie bars between leads which are present during the manufacture of semiconductor devices using a die block and punches cooperating with said die block.
When manufacturing in particular electronic components and more especially integrated circuits, the leads are connected through the package by an enveloping or moulding process. The individual leads are connected together by means of tie bars, which form a limitation for the plastic compound flowing between the leads. These tie bars must be subsequently removed, because they are generally made from the same conductive material as the leads.
For this purpose, it has hitherto been standard practice to place the thus manufactured integrated semiconductor circuits on a die in an accurately positioned manner, followed by the lowering of a punch. This punch has a plurality of comb tooth-like projections, which are introduced between the leads and punch out the tie bars. The tools have hitherto been guided by using of die sets or sliding or roller guides integrated into the tool with circular guide pillars and bushes. It is necessary to accurately guide the die and punch, i.e. for example only a total alignment deviation between the punch and die of a few micrometers is permitted. In hitherto designed tools, more than ten tolerances of tool parts like die inserts, die block, die retainer, dowel holes and pins, position of leader pins and bushings, punch guides and guide inserts etc. accumulate in unloaded condition to the misalignment of punches to the die and furthermore the guiding clearance and misalignment and deformations occuring in the tool under the high forces applied during operation (punching process) add up to the total misalignment of the punches to the die. A high precision guidance is not possible with the aforementioned known tools.
The known tools suffer from the further disadvantage that it is necessary to move and decelerate relatively large masses, which reduces the speed with which the tools work when using mechanical presses.
The goal of the new invention is to develop a tooling system which has a long service life, in which the die and punch are extremely accurately guided and which operates at a high speed.